The present invention relates to a coupling.
One known coupling is from DE 199 46 260 C1. The previously known coupling is provided with a receiving element for receiving a plug-in part configured with a retaining ring. Also present is a securing element provided with two arms and a retaining section, the securing element being insertable into a receiving space of the receiving element and movable perpendicularly to an insertion direction of said plug-in part between an extended position and a pushed-in position. When the securing element is in the pushed-in position, the plug-in part is thereby secured against accidentally slipping out of the receiving element by the engagement of the retaining section behind the retaining ring. It is possible, however, for the securing element to be in the pushed-in position without the plug-in part being properly secured.